1. Field of the Invention
The present invention pertains to the following areas of technology:
MACHINE ELEMENTS AND MECHANISMSxe2x80x94intermittent grip type ratchet and pawl.
2. Description of the Prior Art
U.S. Pat. No. 4,424,724 issued on Jan. 10, 1984 to Bookwalter and assigned to Codman and Shurtleff, Inc. discloses a prior art ratchet mechanism for a retractor assembly. FIG. 1 in Bookwalter discloses the surgical environment where the present invention can be utilized. The present invention is an unobvious improvement over the Bookwalter device.
The present invention is a ratchet mechanism for a surgical retractor assembly. A surgical retractor assembly is illustrated in FIG. 7. FIGS. 1-6 do show not show the correct orientation of the invention when used with the surgical ring. In FIG. 1, the invention should be rotated 180 degrees about the axis of the blade stem. That would then be the position of the mechanisms illustrated in FIG. 7. It should be emphasized that the present invention can be used wherever any dual ratchet mechanism can be utilized and not just in the environment in FIG. 7.
The present invention secures a retractor blade to a ring placed around and above the surgical sight. The present invention has two ratchet and pawl mechanisms described as a rocker ratchet and a pivot ratchet. The rocker ratchet allows the toothed stem portion of the retractor blade to slide back and forth in the housing or ratchet holder. The surgeon can set the distance and the rocker ratchet and pawl mechanism locks the stem in the ratchet holder. The pivot ratchet and pawl mechanism tilts the stem of the retractor blade relative to the ring. The pivot ratchet mechanism allows the surgeon to tilt downwardly the stem and blade tooth by tooth on the pivot ratchet until the angle of inclination is correct. The angle is automatically locked and the blade cannot be raised unless the pivot thumb piece is released to allow the pawl key to be released to allow the blade to be raised upwardly. The pivot ratchet has a transverse slot that fits over the ring in a radial fashion as illustrated in FIG. 1. The slot abuts against the outer edge of the ring, which has indentations. A dowel pin in the slot engages one of the indentations on the ring to help keep the ratchet mechanism from sliding along the ring. As the surgeon pulls on the end of the blade stem to secure the blade in the incision, the counter force of the slot in the pivot mechanism pressing against the outer edge of the ring keeps the mechanism temporarily but securely in position during the surgery. If it becomes necessary, the surgeon can easily adjust the position of the surgical blade by releasing either the rocker thumb piece and/or the pivot thumb piece to reset the distance and tilt of the blade and can then easily relock the stem to its new position. After the surgery, the pieces are all easily separated and sterilized for reuse.